A surrogate key in a database is a unique identifier for either an entity in the modeled world or an object in the database. The surrogate key is not derived from application data. The problem is to deterministically generate a fixed length surrogate key without collisions. A collision or clash is a situation that occurs when two distinct pieces of data have the same hash value, checksum, fingerprint, or cryptographic digest. A cryptographic digest is a deterministic procedure that takes an arbitrary block of data and returns a fixed-size bit string, the cryptographic digest, such that an accidental or intentional change to the data will change the hash value. The data to be encoded is often called the “message”, and the hash value is sometimes called the message digest or simply digest.
The ideal cryptographic hash function has four main properties:
it is easy to compute the hash value for any given message,
it is infeasible to find a message that has a given hash,
it is infeasible to modify a message without changing its hash, and
it is infeasible to find two different messages with the same hash.
Collisions maybe unavoidable whenever members of a very large set (such as all possible person names, or all possible computer files) are mapped to a relatively short bit string.
Prior art systems and methods tend to use variable length keys and may not be deterministic. That is, for sequential solutions of the prior art to the surrogate key problem, a key generated for two identical records may create two separate keys.
Therefore, there is a need to solve the problems associated as described above.